The present invention relates to apparatus for pelletizing plastics in which plastic melt is discharged through die openings in a stationary die plate, and in which a knife head carrying cutting knives is mounted on a shaft so that the knives can be axially moved toward or away from the die surface to effect pelletizing.
U.S. Pat. No. 3,271,821 discloses pelletizing apparatus of the same general type, with a knife shaft being preloaded in advance direction by means of a hydraulic cylinder which is supported by the housing. The cutting knives are fixed by means of screws to the hub of the knife head. During the cutting process, the cutting knives are in contact with the die plate. When the preloaded cutting knives are moved against the die plate, the outside edges of the knives seen in circumferential direction are slightly lifted from the die plate which implies that no clear cut is obtained in the outside areas relative to the circumference. The inside area of the round die plate relative to the circumference is subject to a relatively high pressure exerted by the cutting knives so that this area is exposed to intensive wear.